1 Key Laboratory of Biosafety, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, China CDC, Beijing, China.
2 Beijing Friendship Hospital, Capital Medical University, Beijing, China.
3 Intensive Care Medicine, Beijing Ditan Hospital, Capital Medical University, Beijing, China.
4 Viral Center of National Pathogen Resource Center, China CDC, Beijing, China.
5 Beijing Center for Disease Prevention and Control, Beijing, China.